# 9.3 继承
class Car():
    """一次模拟汽车的简单尝试"""

    def __init__(self,make,model,year):
        """初始化汽车描述的属性"""
        self.make=make
        self.model=model
        self.year=year
        self.odometer_reading=0

    def get_descriptive_name(self):
        """返回整洁的描述性信息"""
        long_name=str(self.year)+' '+self.make+' '+self.model
        return  long_name.title()

    def read_odometer(self):
        print("This car has "+str(self.odometer_reading)+' miles on it.')

    def update_odometer(self,mileage):
        """打印一条指出汽车里程的消息"""
        if mileage>=self.odometer_reading:
            self.odometer_reading=mileage
        else:
            print("You cannot roll back an odometer")


    def increment_odometer(self,miles):
        """将里程表读数增加指定的量"""
        self.odometer_reading+=miles

    def fill_gas_tank(self, gas):
        """汽车油箱还有多少油"""
        print('油箱还有：' + str(gas) + 'ml')



class ElectricCar(Car): # Car在前面，写在括号里
    """电动汽车的独特之处"""

    def __init__(self,make,model,year):
        """初始化父类的属性"""
        super().__init__(make,model,year)
        #super()是一个特殊的函数，调用父类属性
        self.battery_size=70

    def describe_battery(self):
        """打印一条描述电瓶容量的信息"""
        print("This car has a "+str(self.battery_size)+'-kWh battery.')

    def fill_gas_tank(self):
        """电动汽车没有油箱"""
        print('俺们电动汽车没有油箱')


my_tesla=ElectricCar('tesla','model s',2016)
print(my_tesla.get_descriptive_name())
my_tesla.describe_battery()

# 9.3.4 重写父类 直接加定义函数
my_tesla.fill_gas_tank()




